1. Field of Invention
The present invention relates to a new and improved apparatus and method for deaerating or degassing a paper stock suspension.
Generally speaking, the apparatus of the present development for deaerating or degassing a paper stock suspension is of the type wherein partial jets or streams of the paper stock suspension are directed against an impact member, such as an impact wall located within a compartment, for instance, within a first chamber which is at negative pressure. Impacting of the partial jets at the impact member causes spraying or spattering and thus atomization of the paper stock suspension. Air is separated from the sprayed partial jets and the thus separated air is suctionally removed from the first chamber. An enclosure, like a container encloses or delimits the compartment. A distributor or distributor device provided with bores defining throughflow openings introduces the paper stock suspension to be deaerated or degassed into, for instance, a second chamber of the compartment. The distributor is provided with bores defining throughflow openings for the paper stock suspension which is to be deaerated or degassed. The deaerated or degassed paper stock suspension is removed by suitable means, such as a conduit or line from the deaeration apparatus and a further means, such as a conduit or line removes the separated air from the deaeration apparatus.
In the description to follow, the term "deaeration" will be sometimes generally used to encompass both the removal of air and, where appropriate, gases.
2. Discussion of the Background and Material Information
Deaeration or degassing of a paper stock suspension under vacuum conditions, especially at approximately boiling conditions, is required for high-speed papermaking machines where there are fabricated different types of paper like, for example, newsprint paper, light weight coated paper, coated paper, teletype paper, just to mention some of these, from paper stock suspensions containing raw materials, such as, for example, mechanical wood pulp, deinked sorted or classified paper or cellulose. As a general rule, deaeration of the paper stock suspension is performed after there have been removed deleterious or disturbing particles, such as dirt, from the paper stock suspension.
Deaeration is accomplished by different types of deaeration equipment which are quite familiar to those skilled in this technology under commercial trademarks, such as "DECULATOR", "ENSOVAC", "CLEANVAC" or "PERIVAC". With such prior art systems the good stock obtained following a pre-cleaning operation normally from a so-called cleaner battery or array of cleaners, is sprayed against a wall which bounds a compartment in which there is present a high vacuum or negative pressure. As a result, there is caused spraying or atomization of the paper stock suspension, so that the air can rapidly escape from such paper stock suspension. This compartment which is provided for this purpose, must be of considerable size, requiring complicated constructions of the enclosure containers subjected to vacuum conditions.